Most of us live by the 'five second rule', aka the popular notion that food can be picked up off the floor in less than five seconds after falling because bacteria hasn't yet 'contaminated' it.
But Aaron E Carroll, the professor of paediatrics at Indiana University, says we actually have longer than we thought!
“People react to news like this in one of two ways. One is to become paranoid about everything. Such people start to clean compulsively, worry about all the things they’re touching, and use hand sanitiser obsessively,” he told the New York Times.
“The alternative is to realise that for most of us, our immune systems are pretty hardy. We’ve all been touching this dirty stuff for a long time, without knowing it, and doing just fine.
“I clearly fall into the latter group. If I drop food on the floor, I still eat it. I do that because the harm I might get from the floor is not worth my concern compared with many, many other things.”
Dr. Carroll says people should be more concerned with how much bacteria is on other household surfaces - such as the handle of a fridge, the kitchen sink - than on the floor.
“They found that the kitchen floor was likely to harbour, on average, about three colonies per square inch of coliform bacteria (2.75 to be exact),” he added.
“What’s dirtier in the bathroom? Almost everything. The flush handle (34.65 colonies per square inch), the sink faucet (15.84 colonies per square inch) and the counter (1.32 colonies per square inch).
“Things get dirty when lots of hands touch them and when we don’t think about it. We worry about the floor and the toilet seat, so we clean them more. We don’t think about the refrigerator handle or the faucet handle as much.”